Shift Keying Communication System Research Articles

Design and Analysis of Grouping Non-Active Frequency -Time Index Modulation for Differential Chaos Shift Keying Communication System

Design and Analysis of Grouping Non-Active Frequency -Time Index Modulation for Differential Chaos Shift Keying Communication System

A Pattern Modulation Based IRS Scheme for Space Shift Keying Communication System

A Pattern Modulation Based IRS Scheme for Space Shift Keying Communication System

Design of a Short Reference Differential Chaotic Shift Keying Communication System Based on Reference Signal Scrambling Transformation

A short reference differential chaotic shift keying communication system based on reference signal scrambling transformation (RSST-SR-DCSK) is proposed in this paper. The system introduces information-bit-driven scramblers at the transmission end to effectively eliminate the correlation between the reference signal and information signal. At the receiving end, a descrambler is used to restore the correlation, thereby enhancing information transmission security. Additionally, the system employs a short reference transmission mechanism to further increase the information transmission rate. The transmitter and receiver structures of the system are designed through signal structure analysis. Theoretical analyses and simulations conducted in an additive white Gaussian noise (AWGN) channel demonstrate promising performance, including a low bit error rate (BER) and a favorable data-energy-to-bit-energy ratio (DBR). Simulation verification is performed to examine the impact of parameters on the bit error rate performance. A comparative analysis with traditional DCSK and SR-DCSK systems highlights the superior performance of the RSST-SR-DCSK system.

Design and Analysis of Grouping Active Subcarrier Frequency-Time Index Modulation for Differential Chaos Shift Keying Communication System

Design and Analysis of Grouping Active Subcarrier Frequency-Time Index Modulation for Differential Chaos Shift Keying Communication System

Joint Grouping Subcarrier and Permutation Index Modulations Based Differential Chaos Shift Keying System

A joint grouping subcarrier-permutation index modulation based differential chaos shift keying (GSPIM-DCSK) communication system is proposed in this paper in order to enhance the energy and spectral efficiency, and increase the data rate of grouping subcarrier index modulation in DCSK (GSIM-DCSK) system that was recently suggested. In this system, the reference chaotic sequence is loaded into a permutation generator block to construct different permuted replicas of the reference sequence, and the input data bits for each symbol duration are divided equally into G parallel groups, each group consisting of carrier index bits indicated by p1 used for selecting active or inactive subcarrier out of2p1 subcarriers for GSPIM-DCSKI and GSPIM-DCSKII systems respectively, and permutation index bits,p2, that are used to select one chaotic sequence out of 2p2 permuted replicas of the reference chaotic sequence and then used this sequence to spread the modulated bit,p3=1, to send it through active subcarriers so the total number of transmitted bits for GSPIM-DCSKI and GSPIM-DCSKII systems is G (p1+p2+ 1) and G (p1+(2p1-1)(p2 +1)) respectively. The expressions for energy and spectral efficiency, as well as the complexity of the suggested schemes, are determined and compared the outcomes with other traditional DCSK schemes. Under the influence of additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels, the analytical expressions for BER of the two proposed systems are derived. The simulated and analytical BER results are compared to confirm the precision of BER analysis. Additionally, a comparison is made between the findings of the proposed schemes and those of traditional DCSK schemes, indicating that the suggested methods boost the performance of traditional DCSK schemes.

Robust and Energy Efficient Sparse-Coded OFDM-DCSK System via Matrix Recovery

In this paper, we devise a sparse-coded orthogonal frequency division multiplexing (OFDM) differential chaos shift keying (DCSK) communication system based on low-rank matrix recovery which can handle Gaussian background noise and outlier-contaminated symbols simultaneously. As the noise-free OFDM-DCSK symbol matrix has rank 1, we exploit the vector outer product for its modeling, while sparse coding is also applied to reduce the transmission energy. To demodulate information bits from the sparse-coded signal, we formulate an objective function which consists of a sum of Frobenius norm for rank-1 matrix recovery and ℓ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> -norm for identifying the possibly outlier-contaminated symbols, with a self-adaptive weight parameter. The resultant optimization problem is solved iteratively via block coordinate descent, and the Laplacian kernel with the Silverman’s rule is adopted for outlier detection. Theoretical analysis including convergence of the objective function, bit error rate (BER), energy efficiency and computational complexity, are provided. Simulation results show that the proposed system has comparable mean square error and BER performance with the ℓ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>p</i></sub> -norm minimization based matrix recovery approach at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i> = 2 in additive white Gaussian noise, and is superior to that of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i> = 1 in Middleton class A noise, even when sparse coding is applied. Moreover, compared with other binary DCSK systems, our system achieves higher energy efficiency thanks to the sparse coding.

Design and Analysis of a Multi−Carrier Orthogonal Double Bit Rate Differential Chaotic Shift Keying Communication System

A new multi−carrier orthogonal double bit rate differential chaotic shift keying (MC−ODBR−DCSK) communication system is presented in this paper. With two composite signals generated by an orthogonal chaotic signal generator as reference signals, 2M bits of information data are transmitted on M−channel subcarriers, improving transmission speed and energy efficiency. In addition, the receiver does not require a radio frequency (RF) delay circuit to demodulate the received data, which makes the system easier to implement. This paper analyzes Data−energy−to−Bit−energy Ratio (DBR) of the system. The bit error rate performance of the system is simulated to verify the impact of parameters such as chaotic maps, semi-spread spectrum factor, and sub-carrier number. At the same time, the bit error rate performance of the MC−ODBR−DCSK system is compared with traditional DCSK systems in Rician fading and additive Gaussian white noise (AWGN) channels.

Software-Defined Radio Implementation and Performance Evaluation of Frequency-Modulated Antipodal Chaos Shift Keying Communication System

This paper is devoted to software-defined radio (SDR) implementation of frequency modulated antipodal chaos shift keying (FM-ACSK) transceiver and presents results of prototype testing in real conditions. This novel and perspective class of spread-spectrum communication systems employs chaotic synchronization for the acquisition and tracking of the analog chaotic spreading code and does not need resource-demanding cross-correlation. The main motivation of the given work is to assess the performance of FM-ACSK in real conditions and demonstrate that chaotic synchronization can be considered an efficient spread-spectrum demodulation method. The work focuses on the real-time implementation aspects of the modulation-demodulation algorithms, forward error correction (FEC) and symbol timing synchronization approach in MATLAB Simulink. The performance of the presented prototype is assessed via extensive testing, which includes measurement of bit error ratio (BER) in single-user and multi-user scenarios, estimation of carrier frequency offset (CFO) impact and image transmission over-the-air between two independent sites and comparison with classical frequency hopping spread spectrum (FHSS). The paper shows that the presented class of the spread spectrum communication systems demonstrates good performance in low signal-to-noise ratio (SNR) conditions and in terms of BER significantly outperforms the classic spread-spectrum modulation schemes which employ correlation-based detection.

Chaotic-based Orthogonal Frequency Division Multiplexing with Index Modulation

Orthogonal frequency division multiplexing with index modulation (OFDM-IM), stands out among conventional communication technologies, as it uses the indices of the available transmit entities. Thanks to such an approach, it offers a novel method for the transmission of extra data bits. Recent years have seen a great interest in chaos-based communications. The spectrum-spreading signals used in chaotic signal modulation technologies are orthogonal to the existing mixed signals. This paper presents how well a non-coherent differential chaos shift keying communication system performs across an AWGN. Different types of detection methods are simulated, bit error rate and power spectral density are calculated and then compared with standard OFDM with index modulation. The results of simulations concerning the performance of a DCSK system, adding to the security of the proposed solution and offering a comparable bit error rate performance, are presented in the paper as well.

Design and Analysis of Multi-User Faster-Than-Nyquist-DCSK Communication Systems over Multi-Path Fading Channels.

In this paper, we present a new multi-user chaos-based communication system using Faster-than-Nyquist sampling to achieve higher data rates and lower energy consumption. The newly designed system, designated Multi-user Faster Than Nyquist Differential Chaos Shift Keying (MU-FTN-DCSK), uses the traditional structure of Differential Chaos Shift Keying (DCSK) communication systems in combination with a filtering system that goes below the Nyquist limit for data sampling. The system is designed to simultaneously enable transmissions from multiple users through multiple sampling rates resulting in semi-orthogonal transmissions. The design, performance analysis, and experimental results of the MU-FTN-DCSK system are presented to demonstrate the utility of the newly proposed system in enabling multi-user communications and enhancing the spectral efficiency of the basic DCSK design without the addition of new blocks. The MU-FTN-DCSK system presented in this paper demonstrates spectral gains for one user of up to 23% and a combined gain of 25% for four () users. In this paper, we present a proof of concept demonstrating a new degree of freedom in the design of Chaos-based communication systems and their improvement in providing wireless transmissions without complicated signal processing tools or advanced hardware designs.

FPGA-Based Antipodal Chaotic Shift Keying Communication System

The current work presents a novel digital chaotic communication system with antipodal chaotic shift keying modulation, implemented in a field-programmable gate array (FPGA). Such systems provide high security on the physical communication level and can be used in wireless sensor network systems. A modified Chua circuit chaos generator and error linear feedback chaotic synchronization are implemented in FPGA and used to develop a chaotic communication system with digital transmitter and receiver an analog in-between signal transmission. Additionally, a validated mathematical model of the communication system prototype is created in the Simulink environment, which is used to compare the performance of the prototype and its nodes with the simulation and simplify its development. The performance is evaluated using simulation with the additive white Gaussian noise channel and analyzing the bit error ratio.

Multi-carrier DCSK With Hybrid Index Modulation: A New Perspective on Frequency-Index-Aided Chaotic Communication

To realize high energy-efficient, high spectrum-efficient, and high-throughput data transmission, a multi-carrier differential chaos shift keying communication system with hybrid index modulation, referred to as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">HIM-MC-DCSK system</i> , is proposed in this paper. In the HIM-MC-DCSK system, we intelligently integrate the carrier-number-index technique and carrier-index technique into the MC-DCSK modulation in order to significantly boost the transmission efficiency in wireless communication systems. Especially, we use a pair of orthogonal signals to represent the active and inactive subcarriers in the HIM-MC-DCSK system so as to exploit all the subcarriers to transmit information bits. In addition, the theoretical bit-error-rate (BER) expressions of the HIM-MC-DCSK system are derived over additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels. Also, the data rate, spectrum efficiency, energy efficiency, and complexity of the proposed system are carefully analyzed. Monte-Carlo simulations not only verify the accuracy of the theoretical analysis but also illustrate the superiority of the proposed system.

Experimental Study on FM-CSK Communication System for WSN

The current paper presents the experimental study of the frequency-modulated chaos shift keying (FM-CSK) communication system. The proposed system has the potential to enhance the security aspects of the physical layer to meet the needs for safe data transmission in wireless sensor networks (WSN). Compared to common digital FM-DCSK, the studied analog FM-CSK communication system provides a more straightforward design. As chaos oscillators are the core elements of the FM-CSK communication system, the paper investigates the selected oscillators’ properties, including the implementation aspects—the impact of reactive element value deviations on dynamics and synchronization stability. Chaotic dynamics are evaluated with the mean-square-displacement-based 0–1 test, while correlation analysis is used to evaluate synchronization. The impact of the different chaos oscillators’ employment on FM-CSK communication system performance is examined, and the bit error ratio is used for noise immunity evaluation.

THE PERFORMANCE EVALUATION OF MULTI USER OFDM ORTHOGONAL CHAOTIC VECTOR SHIFT KEYING SUPPORTED BY LDPC

Recently, LDPC code have become very important research area in wireless communication due to its ability to increase the capacity in a wireless fading environment, with low implementation complexity. In this paper, LDPC are combined with Multi User OFDM Orthogonal Chaotic Vector Shift Keying (MU-OFDM-OCVSK) communication system to improve the BER performance over multi-path Rayleigh fading channels. Two types of LDPC decoder are introduced that are Log-Domain and Min-Sum decoder. The system is simulated using MATLAB program version 2019a for different scenarios which include different number of iterations, different block lengths, different number of users and different number of spreading factor. The results show that a coding gain in a range of (4.5 – 7) dB is achieved between the coded and uncoded MU-OFDM-OCVSK system. The results also show that the Min-Sum decoder outperform the Log-Domain decoder in all scenarios.&#x0D;

CDSK Modulator and Demodulator System Based on FPAA Technology

Experts have been concerned about the security of digital communication systems and the reduction of interception in recent years. Because of its inherent characteristics and high efficiency in encoding information, chaotic signals can play a significant role in this respect. A dynamically reconfigurable FPAA AN231E04 from Anadigm is used to implement of Correlation Delay Shift Keying (CDSK) communication system. The FPAA chip can be used in almost any electronic hardware for analog system implementations. It permits the experimental selection or amendment of the system structure to achieve its specific properties. The performance of the Rossler oscillator was evaluated via MATLAB Simulink environment. The practical implementation demonstrates and validates chaotic dynamic behavior. The effect of Additive White Gaussian Noise (AWGN) on the performance of the proposed CDSK systems was studied. Under the impact of the AWGN channel, the performance efficiency of the suggested CDSK and noncoherent differential chaos shift keying (NC-DCSK) systems were examined. The CDSK bit transfer technique is safer than the NC-DCSK bit transfer technology. The power consumption of the proposed system is (only 763±18 mW) according to performance studies.

Experimental Study of the Chaotic Jerk Circuit Application for Chaos Shift Keying

Abstract The paper presents a study of the chaotic jerk circuit (CJC) employment capabilities for digital communications. The concept of coherent chaos shift keying (CSK) communication system with controlled error feedback chaotic synchronization is proposed for a specific CJC in two modifications. The stability of chaotic synchronization between the two CJCs was evaluated in terms of voltage drop at the input of the slave circuit and the impact of channel noise using simulations and experimental studies.

Robust receiver for OFDM-DCSK modulation via rank-1 modeling and [formula omitted]-minimization

In this paper, the problem of receiver design for orthogonal frequency division multiplexing differential chaos shift keying (OFDM-DCSK) communication systems is addressed. By exploiting the rank-1 property of the symbol matrix, we propose to apply dimensionality reduction on the time-domain data symbols received from the OFDM-DCSK transmitter for noise reduction, followed by chaotic demodulation on the resultant symbols to decode the information bits. In the presence of additive white Gaussian noise (AWGN), the rank-1 matrix approximation can be simply achieved by the truncated singular value decomposition, corresponding to the solution of ℓ2-norm minimization. While for impulsive noise environments such as in power line communication systems, we develop an alternating optimization algorithm for ℓp-based matrix factorization, where 0<p<2. The bit error rate (BER) of our approach in AWGN is also analyzed and verified. Simulation results demonstrate that the devised receiver is superior to the conventional OFDM-DCSK method in terms of BER and root mean square error performance for AWGN as well as impulsive noise including the Middleton class A distribution and α-stable process.

Design and optimization of multi user OFDM orthogonal chaotic vector shift keying communication system

This paper study and present, power allocation strategy on sub-carriers of multiuser OFDM employed for orthogonal chaotic vector shift keying (MU OFDM-OCVSK) over multipath frequency selective fading channels. firstly, the MU OFDM-OCVSK system is modeled with power allocated on reference and information bearing subcarriers. Then, the computed bit error rate equation of the power allocation MU OFDM-OCVSK system is derived. The optimal power allocation strategy on subcarriers is obtained using convex optimization. Finally, compared with the traditional MU OFDM-DCSK and MU OFDM-OCVSK without power allocation system the proposed system can achieve an excellent BER performance under multipath Rayleigh fading channels. Numerical and Simulation results emphasize the remarkable features of the proposed optimal power allocation strategy.

Design and analysis of grouping subcarrier index modulation for differential chaos shift keying communication system

To sufficiently use the subcarrier index modulation in differential chaos shift keying (DCSK) of the recently suggested carrier index differential chaos shift keying (CI-DCSK) and two-layer carrier index differential chaos shift keying (2CI-DCSK), new subcarrier index modulation based DCSK is proposed and named grouping subcarrier index modulation DCSK (GSIM-DCSK). Two grouping subcarrier index modulations based DCSK systems are proposed named GSIM-DCSK-I and GSIM-DCSK-II systems. The data bits are split into L parallel groups, each group has (p1+p2) bits, where p1 bits are used as indexed bits and p2 are used for a modulated bit. The indexed bits are used as an index selector to select one active subcarrier as in GSIM-DCSK-I or inactive subcarrier as in GSIM-DCSK-II out of 2p index subcarriers. While the modulated bits are modulated by DCSK modulation. The bit error rate (BER) of the proposed systems are derived under additive white Gaussian noise and multipath Rayleigh fading channels, respectively. The simulation results are compared with analytical BER and conventional DCSK modulations. Furthermore, the energy efficiency, spectral efficiency, and complexity analysis are derived and compared with the conventional DCSK modulations. The results show that the proposed systems elevate the performance of the conventional DCSK system.

Time synchronization based on intersatellite lasercommunication links

Time synchronization is essential for navigation, positioning, and timing services. It is widely used in space applications. Laser communication technology is widely used and has the advantages of large communication capacity, strong confidentiality, and anti-interference. In this paper, a time synchronization technique based on laser communication links is proposed. Estimate ranging was realized using the data frame head, and precise ranging was realized by receiving the clock phase. Through theoretical analysis, the theoretical limit of time synchronization accuracy based on laser communication links was obtained, and simulation was performed. Millimeter-level measurement accuracy and picosecond-level time synchronization accuracy can be obtained at a communication rate of 1 Gbps under two-way and one-way ranging conditions. A time synchronization test based on laser communication links was conducted in a laboratory using a coherent binary phase shift keying communication system; test results are consistent with theoretical expectations.